- Aka: internal hamstring reflex
- Procedure:
- Can be tested with the patient either supine or prone.
- In the supine position, the patient’s knee is semiflexed and the hip slightly externally rotated and abducted; the examiner supports the knee with one hand while placing the index finger of the same hand on the medial hamstring tendons, and then strikes this finger with the tendon hammer.2
- In the prone position, the examiner places the index finger on the medial hamstring tendon above the knee joint and then strikes it with a tendon hammer (figure 2).
- A normal response is the visible contraction of the medial hamstring muscles (semitendinosus and semimembranosus), seen best in the prone position.
- The reflex is most useful if it is absent on one side.
- Although one study found it could be elicited in 100% of their population, it may be bilaterally absent in healthy people.
- Predicts L5 radiculopathy
- sensitivity of 76%
- specificity of 85%
- The medial hamstring reflex may particularly help to identify the cause of a foot drop.
- L5 radiculopathy with foot drop occasionally closely mimics a common peroneal palsy, especially early on, including the sensory changes.
- Thus, in addition to assessing for strength of ankle inversion (preserved in a common peroneal palsy since the tibial nerve innervates the tibialis posterior muscle), it may help to assess the medial hamstring reflex (likely preserved in common peroneal palsy).
Made with Bullet